The PP help files list Color Controls with Gamma 1.8 as the first choice and NCA as the second choice for Epson printers in general.
Are you sure that is correct? NCA is always the first choice for colour managed printing and the making of a profile.
Using Colour Control (gamma 1.8 would be the correct choice) means that the driver will still "mess" with the colours in a way that could be inconsistent.
he R1800 should profile ok in NCA mode with the normal target, not the bright one. When I try this, I get a fairly dark target and usable ranges of: 38-255, 51-255, 51-255. With Color Controls, I get 0-255, 0-255, 0-255.
You do not say what type of papers you are profiling; mat papers do tend to give a poor shadow response compared to gloss. I have used PP for mat papers, with NCA and the normal target and found that to be true. This was with an R800. However, satisfactory prints were produced.
I use VueScan too, I don't think the instructions have changed, see attached for my settings. You can ignore the 4 passes setting, not all scanners can do that.
Terry.